1. Field of the Invention
The present invention relates to the counting of corrugations in a material, and more particularly, to the counting of pleats in a flexible material.
2. Description of the Prior Art
A need has existed for an automatic machine for counting the number of pleats in a fabric material. Manual counting not only is time consuming, but is subject to error. The likelihood of such error is increased by the tedius nature of the job.
Problems have existed in the devising of an automatic means for counting pleats. The material is soft and flexible and not easy to handle for automated counting. Where photoelectric counting is considered, a problem exists in that different materials are of different texture and color, thereby varying widely in light reflective characteristics. As a result, some materials have such slight reflection capabilities that the difference in reflective nature between peaks and valleys can not readily be determined. Other materials are so reflective that the reflections from the valleys cannot be distinguished from the reflections from the peaks.
Still another problem is that the spacing between pleats is not uniform. The distance between peaks will vary depending on the heat utilized in their formation. A higher heat will result in more compressed pleats and a lower temperature in wider spacing between the pleats. This variance in spacing from roll to roll of pleated material presents a further problem in automating the counting process.
The need for fast and accurate counting is particularly important where the pleated material is to be used for lampshades.
Commercially, lampshades are manufactured from a continuous roll of pleated material. In assembling the lamp shade it is essential that the lamp shade have a predetermined number of pleats. For example, suppose a lampshade is to be tapered. The manufacturer calculates the number of pleats needed by taking into consideration the size of the shade and height of the pleat. A piece of material hopefully containing the desired number of pleats is cut from the roll. In assembly line practice this desired number was counted manually and marked at each interval where the desired number repeated on the roll. This material, once cut, is then glued and joined at its end to form a sleeve which is then slipped over the lampshade form. If the sleeve does not have the predetermined number of pleats a faulty lampshade will result. If the sleeve has too few pleats it will distort at the bottom thereby stretching the pleats and damaging the saleability of the shade, and thus of the lamp as well. If it has too many pleats, the sleeve becomes loose at the top either before purchase or shortly thereafter thereby resulting in a faulty product.